It is known to provide block systems for the erection of structures such as building walls. Traditionally, structures have been erected by laying superimposed horizontal courses of vertically interlocked simple parallelepipedic hollow concrete blocks, assembled using mortar to connect and seal all joints, thereby providing mechanical and structural properties acceptable in many cases without requiring complex forms and pouring of liquid concrete as needed to erect solid concrete structures. In an attempt to further reduce building costs and accelerate erection time, mortar-less composite interlocking block systems have been proposed in the prior art for enabling dry assembly of block structures, yet contemplating appropriate properties for applications such as in building construction and landscaping. However, such systems are very seldom used in practice for building walls, due to many limitations. Namely, providing appropriate mechanical connections requires the superimposed blocks to be positively locked with each other in order to prevent relative movement in the axial and transversal orientation of the courses. Therefore, many complex interlocking block structures incorporating connection members have been proposed. However, such blocks must be manufactured with tight tolerances and be handled with much care to enable proper block interconnection on the construction site. Still, cement and aggregate based composite materials such as concrete being non compliant and brittle, it is difficult to achieve a stiff and tight fit at block joints even with slight dimensional mismatches or damages. In some cases, separate connectors are used to assist or improve block interconnection.
Another desirable feature for block systems used for building walls is to provide continuous passages inside the walls. While vertical passages are commonly available using most types of hollow building blocks, it is also very desirable to provide openings in the end walls and inner cross members of hollow blocks to define continuous longitudinal passages inside the walls when blocks are laid down in parallel courses. Such passages may be used to pass reinforcing metal rods and pour liquid reinforcing concrete, or to inject or install insulating material such as polyurethane foam, or to run services such as plumbing pipes or electrical or communication wiring or cables from points to points using connecting vertical and horizontal passages.
Accordingly, some solutions have been provided in the prior art which include interconnecting block systems providing different types of integral or separate connecting/locking means, some of these systems also forming longitudinal passages in the erected walls. However, these are not found on the market given their generally poor overall performance and high manufacturing cost.
In U.S. Pat. No. 4,075,808 entitled “Building Construction System Using Mortar-less Modular Building Block Elements” granted to Pearlman on Feb. 28, 1978, hollow interlocking building blocks are provided with a complex structure which enables locking of adjoining superimposed blocks in the axial and transversal horizontal directions. The block structure further provides integrally formed vertically directed recesses and cut-out portions at each lateral end of the blocks for providing communicating vertical and horizontal passages once the wall has been erected. Liquid cement can be poured to form a reinforcing lattice filling passages. The system includes regular blocks, corner blocks, wall end blocks and interior wall connecting blocks. An important limitation of that system is that due to the complex structure of the blocks, block major walls must be thick to provide sufficient mechanical resistance to the brittle free ends and corners, so that for erecting a wall of a given thickness, more block material must be used and less passage space will be available. Therefore, material costs are increased as well as thermal conductivity, and passages would be hard to access from the block surface and would allow very limited space for the passage of services. Also, using non-compliant concrete elements to interconnect blocks limits stiffness and tightness of the assembly and is not well adapted for erecting structures without using stabilizing liquid cement.
U.S. Pat. No. 5,862,640, issued to Negri in January 1999, also teaches hollow building blocks to be placed in direct contact on top and next to one another, where vertical and horizontal voids are provided to enable passage of an interconnected web of vertical and horizontal steel reinforced concrete beams. Although it has a less complex and less damage sensitive structure than that of U.S. Pat. No. 4,075,808, this system for building blast bomb resistant walls does not provide locking or interconnecting means that would prevent axial displacement of the blocks if no added reinforcements were used as intended.
International patent application No WO 94/00648 by Scheiwiller (published on Jan. 6, 1994) and entitled “Set of Building Blocks”, discloses a set of building blocks consisting of a basic block, two end blocks of different length and an optional joint block designed to be laid in a line to build straight or angled walls. The system may also comprise an optional connecting block cooperating with recesses and projections into the building blocks to positively lock them together. However, connecting blocks are solid blocks which prevent continuous longitudinal passages to be formed when a wall is so erected.
European patent application No 0190076 by Cruaud (published on May 2, 1990) and entitled “Bloc de construction et organe de liaison positive associés”, also provides building blocks and a separate connecting element to provide positive lock in the two horizontal orientations of blocks superimposed and vertically interlocked in courses to form walls. Connecting elements comprise an outer rim which cooperates with recesses and cut-outs in the blocks and can have their centre wall punctured so to define horizontal passages in the erected wall. Still, block structure is complex, making molding delicate and costly, and making the brittle concrete block fragile and subject to damages during handling and installation. In addition, narrow recesses may be partly filled with debris on a construction site, which might prevent proper fit of connecting elements.
Therefore, it is desired to overcome or reduce at least some of the above-described problems.